Knee osteoarthritis (OA) is a common degenerative joint disorder and a major cause of pain and disability. The purpose of this study was to investigate the potential effect of Pycnogenol (Horphag Research, Ltd, Geneva, Switzerland), a flavonoid-rich dietary supplement, on the symptoms of knee OA.

Thirty-seven osteoarthritic patients were enrolled in a randomized, double-blind, placebo-controlled trial with parallel-group design. Patients received either placebo or Pycnogenol pills (50 mg, three times daily) in a blinded fashion for 3 months. Osteoarthritis clinical symptoms were evaluated monthly with Western Ontario and McMaster Universities (WOMAC) Osteoarthritis Index. Nonsteroidal anti-inflammatory drugs (NSAIDs) or selective cyclooxygenase 2 (COX-2) inhibitors usage was also assessed.

In the Pycnogenol group, there was a significant improvement in total WOMAC score and WOMAC subscale score of pain and physical function at 60 and 90 days of treatment.

The dosage and frequency of NSAIDs or COX-2 inhibitors usage were increased in placebo group, which were significantly less in Pycnogenol group.

The results of this study indicate the efficacy of Pycnogenol in alleviating osteoarthritis symptoms and reducing the need for NSAIDs or COX-2 inhibitors administration. This beneficial effect of Pycnogenol might be due to its antioxidant and anti-inflammatory properties. Further research is warranted to determine the underlying mechanism associated with this apparent effect.